Pressure gauge



W. WAGNER Aug. 13, 1935.

PRESSURE GAUGE Filed Dec. 12, 1933 r 5 .yh/ m R ma N Tw m N T E IPatented Aug. 13, 1935 more sr'rss Parent rec 4 Claims.

My inventionmore particularly relates to a pressure gauge which mayconveniently be attached to a cylinder and indicates the workingpressure therein, although it will of course, be understood that myinvention is not limited to this particular application.

One of the objects of my invention is the provision of a convenient plugwhich is readily attachable to and detachable from the pressure gaugeproper which may thus readily be changed in order that plugs ofdifferent sizes may be attached thereto for attachment to cylindershaving openings of different sizes or character.

Another object of my invention is the provision of novel means forretaining the indicating member in the position to which it is moved bythe pressure responsive means.

A further object of my invention is the provision of novel pressureresponsive means which coact with the indicating member.

Other objects of my invention will appear in the specification and thenovel features thereof will be particularly pointed out in the claims.

My invention will best be understood by reference to the accompanyingdrawing in which I have illustrated a preferred embodiment thereof andin which- Fig. 1 is a side view of an engine illustrating a cylinderhead to which my pressure gauge is applied;

Fig. 2 is a side view, partially broken away, of the indicator andillustrating it in position in the cylinder head;

Fig. 3 is a vertical section of Fig. 2 but showing the indicating memberin side elevation; and

Fig. 4 is a side view illustrating the indicating member attached to aplug of different size and form.

Like reference characters indicate like parts throughout the drawing.

Referring to the drawing I0 is a cylinder. head provided with a threadedopening H to which is attached a plug l2 provided with a threadedportion I 3 receivable in said opening. The plug is provided with ahexagonal portion l4 to permit the plug to be forcibly inserted by meansof a wrench in its opening to prevent leakage. The plug is provided witha longitudinally-extending opening IS the walls surrounding theupperportion of which are counterbored and threaded as at [6 therebyproviding a recess H.

The indicating device comprises a cylindrical member [8, the lower endof which is threaded as at l9 and receivable in the counterbored portionIt of the plug 12. The outer end of the cylindrical member i8 isprovided with a head 20 formed with a hole 2| preferably rectangular incross section.

A piston 22 is provided with a forwardly extending annular flange 23fitted in the cylinder l8. An indicating member 24 is provided at itsinner end with an enlarged portion 25 preferably cylindrical in crosssection which is received within the flange 23 while the outer portionthereof is'receivable in and movable through said hole 2 i.

The cylindrical member l8 and preferably the head thereof is'providedwith a transverse opening 26 in which is mounted a movable member 2'6,said member 2'8 being forced into engagement with the indicating memberby a spring 28 which is interposed between the member 21 and a screw 29which closes the outer end of the opening 28.

In Fig. 4 I have illustrated a plug l2a of larger size and the threadsof which are a different pitch to accommodate the same to a differentcylinder head having a diiferent sized spark plug opening and providedwith threads of a different pitch from that of the threads shown in Fig.3. By the provision of an indicating member which is readily attached toand detachable from the plug, the plug may readily be changed and a plughaving appropriate threads and of an appropriate size may be provided.The piston is normally forced into its retracted position by a coilspring 30 30 the outer end of which is seated against the head 20 whilethe inner end thereof is seated against the annular flange.

When the plug I2 is attached to the gauge device the bottom portion ofthe piston 22 occupies the position indicated in Fig. 3 in the bottom ofthe recess IT in the plug. Then when the plug l2 of the indicatingmember is inserted in the spark plug opening of a cylinder head, thepressure developed within the cylinder forces the piston 22 and theindicating member 24 outwardly. As soon as the pressure in the cylinderis relieved, the spring 30 forces the piston 22 inwardly independentlyof the indicating member 24 which is retained in the position to whichit is moved by the movable member 21.

By forming the inner end of the indicating member 24 with an enlargedcylindrical portion which is received in the annular flange 23, thelatter serves as a guide for the indicating member in its outwardmovement and prevents any tendency to bind between the outer end of theindicating member and the walls surrounding the hole 2| through which itpasses. The indicating member may readily be forced manually past themember 21 which engages the indicating member rather -lightly.

While I have described my invention in its preferred embodiment, it istobe understood that the words which I have used are words of descriptionand not of limitation. Hence, changes within the purview of the appendedclaims may be made without departing from the true scope and spirit ofmy invention in its broader aspects.

What I claim is:

1. In a pressure gauge, a cylinder provided at its outer end with a headformed with a hole, a pistonprovided with an outwardly extending annularflange fitted in said cylinder, an indicating member the inner end ofwhich is received within said flange and the outer end of which passesthrough said hole, means whereby said cylinder may be connected to areceptacle containing fluid under pressure which is transmitted to saidpiston, said head being provided with a transverse opening, a membermovably mounted in said opening and engageable with said indicatingmember, means for forcing the movable member into engagement with saidindicating member to retain the same in the position to which it ismoved, and means for retracting said piston independently of saidindicating member.

2. In a pressure gauge, a cylinder provided at its outer end with a headformed with a hole, a piston provided with an outwardly extendingannular flange fitted in said cylinder, an indicating member the innerend of which is received within said flange and the outer end 0; whichpasses through said hole, means whereby said cylinder may be connectedto a receptacle containing fluid under pressure which is transmitted tosaid piston, said head being provided with a transverse openingcommunicating with said hole, a member movably mounted in said openingand engageable with said indicating member, means for forcing themovable member into engagement with said indicating member, and meansfor retracting said piston independently of said indicating member.

3. In a pressure gauge, a cylinder provided at its outer end with a headformed with a hole, a piston provided with an outwardly extendingannular flange fitted in said cylinder, an indicating member one end ofwhich is approximately cylindrical in cross section and receivable insaid flange and the other end of which is receivable in and movablethrough said hole, means whereby said cylinder may be connected to areceptacle containing fluid under pressure which is transmitted to saidpiston, the head of said cylinder being provided with a transverseopening communicating with said hole, a member movably mounted in saidopening and engageable with said indicating member, means for forcingthe movable member into engagement with said indicating member, andmeans for retracting said piston independently of said indicatingmember.

4. In a pressure gauge, a cylinder provided at its outer end with a headformed with a hole rectangular in cross section, a piston provided withan outwardly extending annular flange fltted in said cylinder, anindicating member one end of which is approximately cylindrical in crosssection and receivable in said flange and the other end of which isreceivable within and movable through said hole, means whereby saidcylinder may be connected to a receptacle containing fluid underpressure which is communicated to said piston, the head of said cylinderbeing provided with a transverse opening communicating with said hole, amember movably mounted in said opening and engageable with saidindicating member, means for forcing the movable member into engagementwith said indicating member and means for retracting said pistonindependently of said indicating member.

WILLIAM WAGNER.

